TW201410822A - Liquid optically clear photo-curable adhesive for display application - Google Patents

Abstract

A process for reworking an optical assembly and a liquid optically clear photo-curable adhesive, which comprises: (a) 10 to 50 wt% of an urethane acrylate, (b) 30 to 70 wt% of plasticizer, (c) 0.002 to 5 wt% of photo initiator, (d) 1 to 30 wt% of acrylate monomer are described.

Description

Liquid optical transparent light-solid glue for display

This invention relates to a special liquid optically clear light-curing adhesive and to several uses of the adhesive. It further relates to a liquid optically clear photo-curable adhesive substrate and to an optical assembly comprising such an optically clear adhesive. Furthermore, it relates to a method of reworking optical components.

Optically clear adhesives, and in particular liquid optical transparent adhesives, have found widespread use in optical displays. Optical bonding in display applications is used for gluing optical components such as display panels, glass panels, touch panels, diffusers, rigid compensators, heaters, and flexible films such as polarizers and retarders. . The use of such adhesives for bonding touch screens, such as capacitive touch screens, has attracted particular attention. The importance of optically clear adhesives continues to rise as a result of the continued development of new electronic display products, such as e-book readers, for optically clear adhesives. But there are still some challenges that still need to be overcome.

A major challenge with one such optical component is how to reprocess the LCD or other expensive components when defects are found after completion of the press-fit. For example, an end customer may return a bad screen to request after-sales service. In these cases, the display manufacturer must disassemble the display, remove the adhesive residue, and reuse the expensive components such as the LCD module. In the case of a conventional liquid optically clear photo-curing adhesive, after the display is disassembled, the adhesive residue will break into sticky small pieces that adhere to the component. The use of organic solvents to remove this residue is not only extremely time consuming, but also harsh on the environment. Heavy pollution also affects the health and safety of staff.

It is therefore an object of the present invention to make reworking of optical components that have been glued with liquid optically clear photo-curables easier and more practicable. This problem can be solved by the patent of the present invention.

The patent of the present invention is a liquid optical transparent photo-curing adhesive comprising: (e) 10 to 50% by weight of polyurethane acrylate; (f) 30 to 70% by weight, preferably 35 to 70% by weight, most preferably 40 to 50% by weight of a plasticizer; (g) 0.002 to 5% by weight, preferably 0.02 to 3.5% by weight of a photoinitiator; (h) 1 to 30% by weight of an acrylate monomer.

The optically clear adhesive of the present invention has an excellent film forming ability. It forms an optically clear film after complete radiation curing. Reprocessing optical components that have been bonded using the liquid optically clear photo-curing of the present invention are extremely simple and practicable. During the reworking, it is only necessary to disassemble the bonding member after heating to 50 ° C to 100 ° C, and to tear the film which is usually attached to the side of the bonding member. Therefore, the film is easily peeled off from the glue member without leaving any residue on the optical member. The film is preferably peeled off in one piece. The cured adhesive also has a very low modulus of elasticity, very low hardness, very low cure shrinkage and high elongation.

Another advantage of the present invention is that the liquid optically clear light-curing adhesive of the present invention can adhere to components of the optical component, such as bonding a cover lens to an LCD module without any Mura problem. The cured adhesive can pass the rigorous reliability test without the LCD causing plaque (Mura), for example, exposure at 85 ° C for 1000 hours or at -40 ° C for 1000 hours. Usually, Mura is a key issue. "Mura" is a Japanese term for "unevenness." Dark spots or mottles occasionally appear on some liquid crystal display (LCD) panels. This cloud phenomenon is recognized as "Mura". "Mura" is used to describe an inconvenience caused in some cases. Low contrast, irregular graphics or areas of screen consistency. Therefore, Mura is a display effect and can be caused by stress applied to the LCD. Any kind of stress, even at low levels, can cause LCD spots (Mura) to appear. The present invention provides an optimal solution to avoid plaques (Mura).

The term "liquid optically clear photo-curing" is used in the art and is well known to those skilled in the art. Liquid Optical Clear Viscose (LOCA) is widely used in touch panels and display devices to bond cover lenses, plastic or other optical materials to the main sensor or to each other. Liquid optically clear adhesives are commonly used to improve the optical properties of the device as well as to improve other properties such as durability. The liquid optically clear light-curing adhesive is typically used, for example, to bond a touch panel to a primary liquid crystal display, as well as to any cover, such as a lens to a touch panel. The main uses of liquid optically clear photo-curing adhesives include capacitive touch panels, 3D TVs and glass retarders. It specifically means that the adhesive is preferably optically transparent at least 85% of light transmission. Measurement methods for optical transmission are well known to those skilled in the art. Preferably, the measurement is carried out on a sample having a thickness of 100 μm according to the following preferred test method.

A preferred method of transmission measurement: a small drop of optically clear adhesive is placed on a 75 mm by 50 mm wipe with isopropyl alcohol three times and a flat glass slide with a 100 μm thick spacer tape attached to both ends (taken from Dow Corning Corporation, Midland, Michigan) . The second slide was attached to the adhesive under force. The adhesive is then fully cured under the UV light source. The optical transmission rate was measured from a wavelength of 380 nm to 780 nm using an Agilent Cary 300 spectrometer. Use a blank slide as the background.

The adhesive of the present invention has excellent optical properties even under strict and reliable conditions. The adhesive will not yellow after various reliable conditions. The adhesive has a long service life and good processability during lamination.

The adhesive of the invention is suitable for rough surface, can be used for large panels, ideal for filling gaps, avoiding condensation and fogging, tolerating extremely high temperatures, and can be used for extremely thin display panel design.

Polyurethane acrylates are well known to those skilled in the art and can be obtained, for example, by reaction of a diisocyanate, preferably an aliphatic diisocyanate, with a hydroxy acrylate, or from, for example, a diisocyanate. It is a reaction of an aliphatic diisocyanate, a hydroxy acrylate and a polyhydric alcohol.

The polyurethane acrylate preferably contains a polyfunctional polyurethane (meth) acrylate oligomer. The polyurethane (meth) acrylate oligomer preferably contains at least one (meth) acrylate group, for example, from 1 to 4 (meth) acrylate groups. Preference is given to polyfunctional ester acrylate oligomers which are polyfunctional and especially difunctional aliphatic polyurethane acrylate oligomers.

For example, the polyfunctional polyurethane acrylate oligomer can be formed from an aliphatic polyester or a polyether polyol, which is derived from a dicarboxylic acid such as adipic acid or maleic acid, and an aliphatic diol such as diethyl It is made by the condensation of a diol or 1,6-hexanediol. In a particular embodiment, the polyester polyol can contain adipic acid and diethylene glycol. The polyfunctional isocyanate may contain dicyclohexylmethane isocyanate or 1,6-hexamethylene diisocyanate. The hydroxy-functional acrylate may contain a monohydroxyalkyl acrylate such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, or polyethylene glycol acrylate. In a particular embodiment, the polyfunctional polyurethane acrylate oligomer can comprise the reaction product of a polyester polyol, a bicyclohexyl methane isocyanate, and a hydroxyethyl acrylate.

Suitable polyurethane acrylates which can be used in accordance with the invention are, for example, aliphatic polyether polyurethane diacrylates, in particular BR-3042, BR-3641 AA, BR-3741 supplied by Bomar Professionals, Torrington, Connecticut. AB and BR-344.

Other preferred aliphatic polyurethane acrylates are, for example, CN8004, CN-9002, CN-980, CN-981, CN9014, CN-9019, CN9021 supplied by Sartomer Co., Ltd., Exton, Pa. Also preferred is a polyurethane acrylate resin such as Genomer 4188/EHA, Genomer 4269/M22 supplied from Swiss Rahn GmbH. Genomer 4425 and Genomer 1122, Genomer 6043. Also preferred are polyurethane acrylate oligomers such as UV-3000B, UV-3630ID80, UV-3630ID80, UV-NS054, UV7000B and UV-NS077 supplied by NIPPON GOHSEI, Japan, and UC-203 supplied by Kuraray. UC-102. Also preferred are aliphatic polyurethane acrylate oligomers such as Doublemer 5222, Doublemer 5220, Doublemer 5700, Doublemer 5400, Doublemer 5500 available from DOUBLE BOND Chemical Co., Ltd. Bifunctional aliphatic polyester polyurethane acrylate oligomers and difunctional aliphatic polyester/ether polyurethane acrylate oligomers are also preferred polyurethane acrylates.

According to a preferred embodiment of the invention, the plasticizer comprises a polyisoprene resin, a polybutadiene resin, a hydrogenated polybutadiene, a xylene polymer, a hydroxyl terminated polybutadiene and/or a terminal hydroxyl group. Polyolefin. Terpene polymer resins, phthalates, trimellitates, adipates, benzoates, hexanoates and/or dicarboxylates can also be used. Of course, other special plasticizers that are commercially available can also be used.

Suitable plasticizers such as polyisoprene resins, polybutadiene resins, hydrogenated polybutadienes, xylene polymers and the like preferably have a molecular weight (Mn) of from 50 to 50,000 and a functionality of from 0 to 1. . Here, the functionality means a functional group capable of participating in an acrylate, such as an acrylate double bond curing reaction. At this time, the hydroxyl group is not counted to have a monofunctionality.

Preferred polyisoprene resins and/or polybutadiene resins which can be used in the present invention are, for example, polybutadiene polybd45CT, polybd2000CT, poly, supplied from Sartomer Co., Exton, Pa. bd3000CT, CN307. It is preferable to use polyisoprene LIR-30, LIR-50, and LIR-290 supplied from Kuraray Co., Ltd., Tokyo, Japan. It is preferable to use polybutadiene TEA-1000, TE2000, GI-1000, GI-2000, GI-3000, BI-2000, BI-3000, JP-100 supplied from Nippon Soda Co., Ltd., Tokyo, Japan. For example, BI-2000 is a hydrogenated 1,2-polybutadiene homopolymer having a number average molecular weight of about 2,100. E.g, GI-2000 is a hydrogenated 1,2-polybutadiene having a number average molecular weight of about 2,100.

Other preferred plasticizers include, for example, Palatinol 810P, Palatinol DPHP, Plastomoll DNA, supplied by BASF Corporation of New Jersey, USA, and Admex 523 polymeric plasticizer, Admex 6996 polymeric plasticizer, TEG- supplied from Eastman Chemical Company, Tennessee, USA. EH plasticizer (bis(2-ethylhexanoic acid) triethylene glycol ester), DOP plasticizer (di(2-ethylhexyl) phthalate).

Other preferred plasticizers are selected from the group consisting of PB-950, PB-1300, PB-1400, PB-2000, and PB-2400, etc., which are commercially available from Daelim; and may also use Indopol polybutene L50 from BP. , H-7, H-8, H-35, H-50, H-100, H-300, H-1200, H-1500, H-1900, H-2100 and H-6000.

It is also preferred to use a combination of plasticizers such as a combination of bis(2-ethylhexanoate)triethylene glycol ester and polybutadiene resin.

According to a preferred embodiment of the invention is selected from the group consisting of the following photoinitiators or combinations thereof: 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-? Androsolin-1-one, 2-benzyl-2-N,N-dimethylamino-1-(4-morpholinylphenyl)-I-butanone, 1-hydroxycyclohexyl phenyl ketone and Combination of benzophenone, 2,2-dimethoxy-2-phenylacetophenone, bis(2,6-dimethoxybenzhydryl-2,4,4-trimethylpentyl a combination of phosphine oxide and 2-hydroxy-2-methyl-1-phenylpropan-1-one, bis(2,4,6-trimethylbenzylidene)phenylphosphine oxide, 2-hydroxy- 2-methyl-1-phenyl-1-propane, 2,4,6-trimethylbenzimidyl-diphenylphosphine oxide and 2-hydroxy-2-methyl-I-phenylpropan-1 a combination of ketones, 2,4,6-trimethylbenzimidyldiphenylphosphine oxide.

According to a preferred embodiment of the invention, the acrylic monosystem is selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-(2-ethoxyethoxy) Ethyl acrylate, tetrahydrofuran methyl (meth)acrylate, lauryl acrylate, isooctyl acrylate, propylene Isodecyl phthalate, 2-phenoxyethyl acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate , (di) pentadienyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, acrylic acid Lactone, morpholine (meth)acrylate, hexylene glycol di(meth)acrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and combinations thereof.

It is also possible to coat the acrylate oligomer, which preferably has a Tg value from -80 ° C to 100 ° C. The acrylate oligomer is preferably prepared from a (meth)acrylic monomer and preferably has a weight average molecular weight (MW) in the range of from about 1000 to 15,000. A preferred weight average molecular weight (MW) can be about 2,000.

The MW can be determined by gel permeation chromatography (GPC). Determination of molecular weight by gel permeation chromatography is well known and widely employed in the related art. In the measurement, for example, polystyrene having a narrow molecular weight distribution may be used as a standard, and tetrahydrofuran may be used as a mobile phase, and the flow rate may be, for example, 0.8 mL/min, and the column temperature may be, for example, 35 °C.

In general, (meth) acrylate refers to a functional group having both acrylate and methacrylate. Generally, "acrylate" refers to both acrylate and methacrylate functional groups. "Acidyl ester" also refers to both acrylic ester and methacrylic ester functional groups.

The adhesive of the present invention has an ultra-low hardness and an ultra-low modulus of elasticity as shown. Thus, in accordance with a preferred embodiment of the present invention, the cured modulus of the cured adhesive is <1.0.104 Pa, which is preferably measured by photofluidometry.

Measurement of the modulus of elasticity is well known to those skilled in the art. The photofluidometry is preferably used when measuring the modulus of elasticity. This is a convenient and well established technique for measuring elastic modulus and is well known to those skilled in the art.

A photofluid assay that can be applied to the measurement of elastic modulus, which operates as follows: Preferably, the photofluidometry is carried out using a Physica MCR301 optical rheometer from Anton Paar Co., Ltd., Germany. The optical rheometer has a pair of parallel plates and its bottom plate is made of quartz. Curing glue from a high-pressure mercury arc (HPMA) lamp (93mW/cm2 ultraviolet light intensity) through an oscillating mode (at a fixed angular frequency of 30 rad/s and 0.5% strain) to cure the adhesive between the parallel plates Interlayer (1.00mm initial gap). The modulus was recorded in the UV curing time. Zero fixed forward force (Fn) is used to automatically reduce the gap to accommodate the shrinkage of the sample during curing.

According to another preferred embodiment of the present invention, the hardness of the cured adhesive when measured according to ASTM D 2240 is <10 (Shore hardness 00), preferably 3 (Shore hardness 00).

Hardness measurement according to ASTM D 2240 is well known to those skilled in the art. The hardness measurement is preferably carried out according to the following method: curing the liquid optically clear adhesive in a flat-bottomed container. The amount of the adhesive is controlled so that the cured adhesive has a thickness of about 6.4 mm. The sample was placed on a hard flat bottom surface. Press the indenter of the hardness tester (Rex Gauge, Model 1600 Dial-OO, Ill., USA) into the sample and make sure it is parallel to the surface. Firmly contact the sample to measure its hardness within one second.

According to another preferred embodiment of the present invention, the shrinkage of the cured adhesive is measured by photofluidometry to be <1, 5%, preferably 1%.

Preferably, the curing shrinkage ratio is measured by a photofluid measurement method. This is a convenient and well established technique for measuring shrinkage and is well known to those skilled in the art.

A photofluid assay that can be applied to measure shrinkage, operating as follows: Preferably, the photofluid assay is performed using a Physica MCR301 optical rheometer from Anton Paar, Germany. The optical rheometer has a pair of parallel plates and its bottom plate is made of quartz. Curing glue from a high-pressure mercury arc (HPMA) lamp (93mW/cm2 ultraviolet light intensity) through an oscillating mode (at a fixed angular frequency of 30 rad/s and 0.5% strain) to cure the adhesive between the parallel plates Interlayer (1.00mm initial gap). The modulus was recorded in the UV curing time. The zero fixed positive force (Fn) is used to automatically reduce the gap to accommodate the shrinkage of the sample during curing. Paint with clearance to cure time The linear cure shrinkage curve of the sample was obtained.

According to another preferred embodiment of the invention, the cured adhesive has an elongation of >500%.

According to the elongation of the above specific examples, the elongation at break is defined as follows: elongation at break = (L - L0) / L0 * 100%; L0: standard length; L: elongation at break. The elongation was measured at room temperature (25 ° C).

All measurements or test methods in the present invention were carried out at room temperature (25 ° C) unless otherwise stated.

Determination of elongation at break is well known to those skilled in the art. The determination of elongation can be carried out, for example, according to ASTM D 882 with an Instron instrument.

Preferably, the method for determining the elongation by a tensile tester is as follows: Sample preparation: prepared by dropping the adhesive composition onto a PET-film having a release agent (for example, coated with a silicone release agent). A sample of thickness (0.6 mm) was irradiated with ultraviolet light and cured, and then the fully cured sample was cut into a known size of 0.6 mm * 10 mm * 50 ~ 60 mm.

Preferably, the tensile test is performed by an Instron tester (Instron universal testing machine): test area: 0.6 mm * 10 mm * 30 mm (clamp is 20 ~ 30 mm)

Load capacity: 1KN

Speed: 300mm / min

The adhesive of the invention can achieve extremely low hardness, shrinkage and elastic modulus, and it contains: (a) 30 to 45 wt% of polyurethane acrylate; (b) 35 to 50 wt% of a plasticizer; (c) 0.02 to 3.5 wt%, preferably 1 to 3.5 wt%, most preferably 1 to 2 wt% Photoinitiator; (d) 15 to 25 wt% of acrylate monomer.

Such adhesives allow for easy and rapid rework of optical components utilizing the adhesive combinations of the present invention. For example, the film is easily peeled off from the cover lens or display panel after heating to 50 ° C to 100 ° C without leaving any residue on the optical component. The film can be removed in one piece.

A preferred adhesive composition of the present invention thus comprises: (a) 30 to 45 wt% of a polyurethane acrylate; (b) 35 to 50 wt% of a plasticizer; (c) 0.02 to 3.5 wt%, preferably 1 to 3.5 wt% of photoinitiator; (d) 15 to 25 wt% of acrylate monomer. The cured adhesive preferably has a modulus of elasticity of <1.0.104 Pa when measured by photofluidometry.

A preferred adhesive composition of the present invention thus comprises: (a) 30 to 45 wt% of a polyurethane acrylate; (b) 35 to 50 wt% of a plasticizer; (c) 0.02 to 3.5 wt%, preferably 1 to 3.5 wt% of photoinitiator; (d) 15 to 25 wt% of acrylate monomer. Preferably, the cured adhesive has a <1.5% when measured by photofluidometry, preferably 1% shrinkage.

A preferred adhesive composition of the present invention thus comprises: (a) 30 to 45 wt% of a polyurethane acrylate; (b) 35 to 50 wt% of a plasticizer; (c) 0.02 to 3.5 wt%, preferably 1 to 3.5 wt% of photoinitiator; (d) 15 to 25 wt% of acrylate monomer. The cured adhesive preferably has a 0 to 0 when measured according to ASTM D 2240 10 (Shore hardness 00), more preferably 0 to 3 (Shore hardness 00) hardness.

A preferred adhesive composition of the present invention thus comprises: (a) 30 to 45 wt% of a polyurethane acrylate; (b) 35 to 50 wt% of a plasticizer; (c) 0.02 to 3.5 wt%, preferably 1 to 3.5 wt% of photoinitiator; (d) 15 to 25 wt% of acrylate monomer. Its cured adhesive has an elongation of >500%.

A preferred adhesive composition of the present invention thus comprises: (a) 30 to 45 wt% of a polyurethane acrylate; (b) 35 to 50 wt% of a plasticizer; (c) 0.02 to 3.5 wt%, preferably 1 to 3.5 wt% of photoinitiator; (d) 15 to 25 wt% of acrylate monomer. The shrinkage of the cured adhesive when measured by photofluidometry is <1.5%, preferably <1%; the cured adhesive preferably has 0 to 0 when measured according to ASTM D 2240 10 (Shore hardness 00), preferably 0 to 3 (Shore hardness 00) hardness; the cured adhesive is preferably having an elastic modulus of <1.0.104 Pa when measured by photo-fluidometry; and the elongation of the cured adhesive is >500%.

The adhesive composition according to the invention may, of course, contain additional optional ingredients. It is well known to those skilled in the art.

The most preferred additional ingredients are selected from the group consisting of tackifiers, defoamers, antioxidants, and adhesion promoters.

Adhesives are well known and used to improve the viscosity or other properties of adhesives. quality. There are many different types of tackifiers, but almost any tackifier can be classified as a rosin resin derived from wood rosin, gum rosin or tall oil rosin; a hydrocarbon resin made from petroleum based materials. Or a terpene resin derived from wood or certain fruit tree terpene raw materials. The adhesive contains, for example, from 0.001 wt% to about 20 wt%, from 0.01 wt% to about 15 wt%, or from 0.1 wt% to about 10 wt% of a tackifier. The tackifier is also substantially free of tackifiers, for example from 0.001 wt% to about 5 wt% or from about 0.001 wt% to about 0.5 wt%, based on the total amount of tackifier. The adhesive may also be completely free of tackifiers.

The liquid optically clear photo-curable of the present invention can be prepared by mixing all of the ingredients to obtain a homogeneous mixture away from light.

Another application of the present invention is a method for bonding a top substrate to an underlying substrate, wherein (a) applying a liquid optically clear optical adhesive as described above to a top surface of the underlying substrate; (b) the top substrate contacting step (a) on the adhesive layer; (c) hardening the adhesive by exposing electromagnetic radiation having a wavelength ranging from 200 nm to 700 nm, preferably from 250 nm to 500 nm.

By "underlying substrate" is meant herein a substrate to which a top substrate is attached. The "underlying substrate" can be, for example, a display panel or an LCD. The optically clear photocurable adhesive is preferably applied to the top surface of the underlying substrate. The "top substrate" is, for example, a cover lens.

Preferably, the top substrate of the transparent substrate is preferably attached to the adhesive layer under ambient or vacuum conditions. Vacuum conditions specifically refer to the absence of any air bubbles in the bonding surface. If it is under vacuum conditions, the degree of vacuum should preferably be <100 Pa, preferably <10 Pa.

By "substantially transparent" herein is meant a suitable substrate for optics having a transmittance of at least 85% in the range of 380 to 780 nm.

According to a preferred embodiment of the present invention, the top surface of the underlying substrate is selected from the group consisting of glass And a polymer, preferably a plastic film, including, in particular, polyethylene terephthalate, poly(methyl) acrylate, and/or cellulose triacetate (TAC). A plastic film is a sheet of material (preferably a polymer and preferably transparent) covering the article. A preferred underlying substrate is an LCD module having a polarizing film thereon. In a preferred embodiment, the cellulose triacetate is placed on the top surface of the polarizer. Thus, at this point, the adhesive will be bonded directly to the cellulose triacetate surface.

According to another preferred embodiment of the present invention, the side of the top substrate to be bonded to the transparent substrate is selected from the group consisting of glass and polymer, preferably a plastic film, including polyethylene terephthalate, specifically Methyl (meth)acrylate, and/or cellulose triacetate.

According to another preferred embodiment of the present invention, the substrate can be a display panel, preferably selected from the group consisting of a liquid crystal display, a plasma display, a light emitting diode (LED) display, an electrophoretic display, and a Cathode ray tube display.

The display panel is preferably provided with a touch function.

According to another preferred embodiment, the top substrate is selected from the group consisting of a reflector, a cover lens, a touch panel, a retardation film, a retarder glass, an LCD, a lenticular lens, a mirror, and an anti-glare. Or an anti-reflective film, an anti-splinter film, a diffuser or an electromagnetic interference filter. For example, in a 3D television application, a glass or film polarizer is bonded to a passive 3D television LCD or a twisted nematic liquid crystal (TN LCD), or a lenticular lens is bonded to a conventional TFT LCD of a stereoscopic 3D television.

The adhesive of the present invention, as well as the method of the present invention, can be used with any touch panel sensor assembly. It is preferably used to bond a touch sensor that requires two layers of indium tin oxide conductive glass. It is preferably used for the bonding of a cover lens, especially an air gap in a touch panel sensor using a cover lens (for example, transparent plastic poly(methyl) methacrylate) and a glass touch panel sensor. Preferably, it is directly used for bonding, and it is preferred to directly bond the cover lens to an LCD module.

Of course, the invention comprises two or more top substrates that are sequentially bonded to the underlying substrate The board, for example, first uses an LCD as the underlying substrate, and then adheres a layer of indium tin oxide conductive glass to the underlying substrate by means of a liquid optically transparent photo-curing adhesive, and then adheres to another layer by liquid optically transparent photo-curing. The indium tin oxide conductive glass is finally bonded to the cover lens by a liquid optical transparent photo-curing adhesive.

Another object of the present invention is a method of manufacturing an optical component, comprising the steps (a) to (d): (a) providing a display panel and a top substrate, preferably a cover lens or a touch panel; b) applying the adhesive of the present invention to the display panel; (c) attaching the top substrate to the adhesive layer of step (b); (d) curing by exposure to electromagnetic radiation having a wavelength of 200 nm to 700 nm Liquid optical transparent light solid glue.

The liquid optically clear optical adhesive applied to the top surface of the display panel in the process preferably has a liquid optical transparent adhesive formed to have a thickness of 50 μm to 600 μm. The adhesive is preferably coated in a continuous layer.

The optically clear photo-curing can be applied by conventional methods, such as by single or multiple nozzles or a slit coater.

Electromagnetic radiation, especially ultraviolet radiation, is applied using, for example, a high intensity continuous emission system taken from the Fusion UV system until the adhesive is fully cured. Metal halide lamps, LED lamps, high-pressure mercury lamps, xenon lamps, xenon flash lamps, etc. can be used when using ultraviolet radiation. The UV energy should be between about 100 and 5,000 mJ/cm ² . For example, the irradiation time may be from several seconds to several tens of seconds, for example, from 5 to 30 seconds or longer when needed. Those skilled in the art can easily measure their radiant power and exposure time.

Another object of the present invention is a reworking method for an optical component produced by using the adhesive according to the present invention, preferably according to the above method, comprising the step (a) To (c): (a) detaching the top substrate, preferably the cover lens or the touch panel, from the display panel by heating the assembly to about 50 ° C to 100 ° C, and then removing the top substrate; (b) After the top substrate is detached, the removal member is cooled to room temperature (25 ° C); (c) the residual adhesive is peeled off from the top substrate and/or the display panel.

Preferably, the optical component comprises a display panel, in particular a display panel and a top substrate, which is preferably a substantially transparent substrate and an adhesive layer disposed between the display panel and the top substrate.

Another application of the present invention is to use the liquid adhesive composition of the present invention on a display to be fixed to a touch screen on an underlying substrate. The substrate can be a display panel, preferably selected from the group consisting of a liquid crystal display, a plasma display, a light emitting diode (LED) display, an electrophoretic display, and a cathode ray tube display.

According to another preferred embodiment of the present invention, the top substrate is selected from the group consisting of a reflector, a cover lens, a touch panel, a retardation film, a polarizing glass, an LCD, a lenticular lens, a mirror, an anti-glare or an anti-glare A reflective film, a shatterproof film, a diffuser, or an electromagnetic interference filter. For example, in a 3D television application, a glass or film polarizer is bonded to a passive 3D television LCD or a twisted nematic liquid crystal (TN LCD), or a lenticular lens is bonded to a conventional TFT LCD of a stereoscopic 3D television.

Another application of the present invention is the use of the liquid optically clear light-curing adhesive for bonding optical component parts, wherein the cured adhesive is preferably peeled off after heating to 50 ° C to 100 ° C.

"The cured adhesive is peeled off after heating" means that the bonded parts can be removed when heated to about 50 ° C to 100 ° C, and the separated parts can be cooled to room temperature (25 ° C), and then The residual film can be peeled off from one or two pieces of the peeling member, and the film is preferably peeled off in one piece. This setting The following applies to the following specific examples of the invention.

Another application of the present invention is a liquid optical transparent optical adhesive for use in a touch panel sensor assembly, preferably for bonding a touch panel sensor requiring two layers of indium tin oxide (ITO) conductive glass, wherein the cured adhesive layer The glue is preferably peeled off after heating to 50 ° C to 100 ° C.

Another application of the present invention is the use of the liquid optically transparent optical adhesive for the bonding of a cover lens, preferably for filling an air gap of a touch panel sensor using a cover lens and a glass touch panel sensor, wherein the The cured adhesive is preferably peeled off after heating to 50 ° C to 100 ° C.

Another application of the present invention is the use of the liquid optically clear optical adhesive for directly bonding a cover lens to an LCD module, wherein the cured adhesive is preferably peeled off after heating to 50 ° C to 100 ° C.

Another object of the present invention is the liquid optical transparent photo-curable composition on the display for fixing the touch screen on the bottom substrate, wherein the bottom substrate can be a display panel, preferably selected from a liquid crystal display, A plasma display, a light emitting diode (LED) display, an electrophoretic display, and a cathode ray tube display, wherein the cured adhesive is preferably peeled off after heating to 50 ° C to 100 ° C.

Another application of the present invention is the use of the liquid adhesive composition of the present invention for preventing spots (Mura) in optical components.

The adhesive of the present invention can be applied to mobile phones, desktop computers, televisions, notebook computers, digital cameras, photo frames, car navigation systems, outdoor display screens and the like in all fields.

Instance

A homogeneous mixture away from light is obtained by mixing the following ingredients to prepare the following liquid optically clear light-curing gel.

The use of the liquid optically clear optical adhesive in the manufacture of an optical component (Example a) comprises: (a) providing a display panel and a cover lens; (b) placing the liquid optically clear optical adhesive on the display panel (c) placing a cover lens on the adhesive layer of step (b); (d) exposing the optical component to electromagnetic radiation having a wavelength ranging from 200 nm to 700 nm.

The liquid optically clear light-curing adhesive enables the cover lens to be bonded to the display panel without any problems of the Mura. Even when the pressure is applied to the display panel, the spot (Mura) cannot be detected. An optical component having the cured adhesive of the present invention passed various reliability tests (85 ° C × 1000 hours; 60 ° ° and 95% relative humidity × 1000 hours; -40 ° C × 1000 hours; thermal cycle: -40 ° C to 85 ° C × 1000 cycles) No problem with Mura.

The cured adhesive exhibits the following properties: ● Excellent film forming ability; ● High elongation > 500%; ● Ultra-low elastic modulus: <1.0 x 104Pa; ● Ultra-low hardness: <10 (Shore hardness 00); ● Ultra-low cure shrinkage: <1%.

The optically clear adhesive of the present invention significantly improves the reworkability of the assembled display.

A method for reworking an optical component (Example b) which is assembled using the adhesive of the present invention (see Example a) according to the following steps (a) to (c): (a) by heating the assembly Decoupling the cover lens from the display panel to about 90 ° C and removing the cover lens; (b) after removing the cover lens, cooling the take-up member to room temperature (25 ° C); (c) tearing off the cover lens Residual film.

The film can be easily removed from the cover lens without leaving any residue on the optical component. The film is peeled off in a single monolith.

Claims (15)

A liquid optically clear light-curing adhesive comprising: (a) 10 to 50% by weight of a polyurethane acrylate; (b) 30 to 70% by weight of a plasticizer; (c) 0.002 to 5% by weight of a photoinitiator; (d) 1 to 30% by weight of an acrylate monomer. The adhesive composition according to claim 1, wherein the polyurethane acrylate is an aliphatic polyether polyurethane acrylate or acrylate. The adhesive composition according to claim 1 or 2, wherein the plasticizer comprises a polyisoprene resin, a polybutadiene resin, a hydrogenated polybutadiene, a xylene polymer, and a terminal Hydroxy polybutadiene and/or hydroxyl terminated polyolefin. The viscose composition according to any one of claims 1 to 3, wherein the photoinitiator is selected from the group consisting of 1-hydroxycyclohexyl phenyl ketone and 2-methyl-1-(4-) Methylthiophenyl)-2-morpholinylpropan-1-one, 2-benzyl-2-N,N-dimethylamino-1-(4-morpholinyl)-1-butanone , a combination of 1-hydroxycyclohexyl phenyl ketone and benzophenone, 2,2-dimethoxy-2-phenylacetophenone, bis(2,6-dimethoxybenzamide-2 , a combination of 4,4-trimethylpentyl)phosphine oxide and 2-hydroxy-2-methyl-1-phenylpropan-1-one, bis(2,4,6-trimethylbenzylidene) Phenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propane, 2,4,6-trimethylbenzimidyl-diphenylphosphine oxide and 2-hydroxy-2- A combination of methyl-1-phenylpropan-1-one and 2,4,6-trimethylbenzimidyldiphenylphosphine oxide. The adhesive composition according to any one of claims 1 to 4, wherein the acrylic single system is selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, (methyl) ) butyl acrylate, ethyl 2-(2-ethoxyethoxy)acrylate, tetrahydrofuran methyl methacrylate, lauryl acrylate, isooctyl acrylate, isodecyl acrylate, 2-phenoxyethyl acrylate , 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopenteneoxy (meth)acrylate Ester, dicyclopentadienyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, acrylic acid Caprolactone, morpholine (meth)acrylate, hexylene glycol di(meth)acrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and combinations thereof. The adhesive composition according to any one of claims 1 to 5, wherein the cured adhesive has an elastic modulus of <1.0.104 Pa, which is preferably measured by photofluidometry. . The adhesive composition according to any one of claims 1 to 6, wherein the shrinkage of the solid adhesive is <1.5%, preferably 1%, which is preferably measured by photofluidometry. The adhesive composition according to any one of claims 1 to 7, wherein the cured adhesive has a hardness of 0 to 10 (Shore hardness 00), preferably 0 to 3 (Shore hardness 00), which is preferably measured according to the hardness measurement method of ASTM D 2240. The adhesive composition according to any one of claims 1 to 8, wherein the cured adhesive has an elongation of >500%. The adhesive composition according to any one of claims 1 to 9, which comprises: (a) 30 to 45 wt% of a polyurethane acrylate; (b) 35 to 50 wt% of a plasticizer; (c) 0.02 to 3.5% by weight of a photoinitiator; (d) 15 to 25% by weight of an acrylate monomer. The adhesive composition according to any one of claims 1 to 10, which contains an additional component preferably selected from the group consisting of a tackifier, an antifoaming agent, an antioxidant, and an adhesion promoter. A method of manufacturing an optical component, comprising the steps (a) to (d): (a) providing a display panel and a top substrate, preferably a cover lens or a touch panel; (b) applying the adhesive according to any one of claims 1 to 11 to the display panel; (c) attaching the top substrate to the adhesive layer of the step (b) (d) curing the liquid optically clear photo-curing adhesive by exposure to electromagnetic radiation having a wavelength of from 200 nm to 700 nm. A method for reworking an optical component, the combination of which utilizes the adhesive according to any one of claims 1 to 11, preferably according to the method of claim 12 And comprising the steps (a) to (c): (a) disengaging the top substrate of the cover lens or the touch panel from the display panel by heating the assembly to about 50 ° C to 100 ° C, and then removing the The top substrate; (b) after the top substrate is detached, the removal member is cooled to room temperature (25 ° C); (c) the residual adhesive is peeled off from the top substrate and/or the display panel. The use of the liquid optically clear light-curing adhesive according to any one of claims 1 to 11, wherein the cured adhesive is preferably heated to 50 ° C to 100 ° C. Can be torn off. A use of a liquid adhesive composition according to any one of claims 1 to 11 for preventing a spot (Mura) in an optical component.